1. Field of the Invention
The present invention relates to a display apparatus and more particularly to a display apparatus of a power saving type used in a personal computer or the like.
2. Description of Related Art
In recent years, for example, in the field of a display apparatus such as CRT (Cathode Ray Tube) display or the like, there has intensively requested a reduction in power consumption inclusive of a countermeasure for prevention of global warming. Particularly, in the case of a CRT display, power consumption is large compared with that of liquid crystal and a further low power formation is requested. For such purpose, there has been adopted a method in which a situation of using, for example, a keyboard or a mouse in a personal computer or a word processor is monitored and power is automatically saved when it is not used for a constant period of time. Further, in a personal computer or the like, there is achieved a reduction in power consumption by darkening a screen of a personal computer or the like by a xe2x80x9cscreen saverxe2x80x9d darkening only a video signal to thereby achieve prevention of burning of a CRT display as well.
FIG. 3 is a block diagram showing a constitution of a personal computer 2 and a display apparatus 1 having a conventional power saving function. The personal computer 2 monitors a situation of using a keyboard 21 or a mouse 22 and when the personal computer 2 determines that they are not used for a predetermined period of time, the personal computer 2 makes OFF horizontal and vertical synchronizing signals and outputs a sign of power saving to the display apparatus 1. The side of the display apparatus 1 detects the sign by a micro controller 11 and reduces power consumption by controlling to cut a power source 12 or stop deflection of a deflection circuit 13 based on the detection.
Further, according to JP-A-3-46022, a personal computer is installed with a sensor for detecting approach of an operator and makes a display portion of a CRT display or the like function when the operator approaches. Although in this example, there is no explanation of a case of bringing about a power saving state, it seems that the power saving state is brought about when approach of the operator is not detected for a predetermined period of time or when the display is not used for a predetermined period of time.
However, there pose problems in such examples.
1) The power saving state is brought about when it is detected that a personal computer is not used over a certain constant time period or the power saving state is brought about when the operator leaves over a predetermined time period and the display unit functions when the operator approaches the screen and accordingly, power saving cannot be carried out at an arbitrary occasion. That is, power saving is carried out by detecting that the screen is not used or the user leaves therefrom and accordingly, a wait time period to some degree is needed for the personal computer to determine that the screen has not been used.
2) In the case of a system in which it is not only a monitor that can carry out power saving, when a host apparatus executes a job which does not need to display (for example, reproduction of a digital audio signal), even if only power of the monitor is intended to save, the power cannot be saved.
3) Even when a power saving button is installed to a personal computer, it cannot be simply operated in the case where the personal computer is put under a desk or the like. Further, the method of carrying out power saving from the side of a personal computer is difficult to know by a user and poses many problems in operation.
4) When a signal source having no power saving function as in VTR (Video Tape Recorder) is connected, power saving cannot be brought about.
5) Even when a monitor is brought into power saving, in the case where the host side cannot detect the situation, operation of the monitor cannot be recovered by key input or the like.
As described above, according to the conventional display apparatus, there poses a problem in which power saving cannot be executed at arbitrary time and the side of the display apparatus cannot bring about the power saving state by itself. Further, the operation of power saving must be carried out and the side of a personal computer and accordingly, there poses a problem in operability.
The present invention resolves the above problem and realizes a display apparatus capable of bringing about a power saving state by itself at arbitrary time on the side of a display apparatus and capable of instantaneously informing a host side that the power saving state is brought about by a comparatively simple method.
In order to resolve the above-described problem, according to an aspect of the present invention, there is provided a display apparatus having a power supply circuit and a display circuit and connected to an information processing apparatus for carrying out character display or graphic display in accordance with information transmitted from the information processing apparatus, the display apparatus comprising power saving switch means for instructing a shift to a power saving mode for reducing power consumption, and control means for determining input of the power saving switch means and controlling the power source circuit and/or the display circuit to shift to the power saving mode.
Further, according to other aspect of the present invention, there is provided a display apparatus having a power supply circuit and a display circuit and connected to an information processing apparatus for carrying out character display or graphic display in accordance with information transmitted from the information processing apparatus, the display apparatus comprising remote operation instruction receiving means for receiving a signal from an outside remote operation means, and control means for determining that the remote operation instruction receiving means receives an instruction to shift to a power saving mode from the outside remote operation means and controlling the power supply circuit and/or the display circuit to shift to the power saving mode.